Memory card with capacity-independent 3-line addressing system

ABSTRACT

A portable electronic smart card for use as a medium for the dissemination among consumers of digitized data such as texts, pictures or game programs. The smart card is connected to user systems through a reduced set of contacts including, regardless of capacity, 3 contacts for transmitting address signals (CA1, CA2, INC/DEC), 8 contacts for transmitting data signals (D0-D7), and 5 different leading and control signals (VCC, VPP, GND, PGM, OE). For memory addressing, the card contains two up-down counter (11 and 12) which receive pulses from lines CA1, CA2 and INC/DEC.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of PCT applicationPCT/FR91/00785 filed 7 Oct. 1991.

FIELD OF THE INVENTION

The present invention relates generally to a memory card intended forstoring information and having the size of a credit card.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an edge view of a prior-art first type of memory card;

FIG. 2 is a perspective view of a prior-art second type of memory card;

FIG. 3 is a schematic diagram illustrating the instant invention; and

FIG. 4 a top view showing the layout of the external contacts of thecard according to the invention.

BACKGROUND OF THE INVENTION

The telephone card, a so-called telecard, is known which actually has ina silicon chip a wired circuit permitting the storage of several memoryregisters corresponding to prepayed telephone units.

Another memory card, called a chip card, is now known which is basedessentially on a microprocessor chip (CPU) which gives security orconfidentiality to a limited amount of information representing eitherfinancial information (charge cards), personal information (medicalrecords, university records), codes for access to certain locations, oreven a combination of this information. Access to the information isgained by a serial connection through a single conductor through themicroprocessor with the help of a complex set of instructions fortransmission.

The use of microprocessor on the silicon chip takes up space and doesnot permit the addition of a very large memory capacity.

FIG. 1 shows the two types of cards described above. They employ for theelements that use them an array of ISO-type connectors (standard ISO7816-2) whose number is reduced to eight. This allows the easymanufacture of these cards simply by adhering and connecting the chip 1to the back of a small contact unit 2 made by depositing conductors on afilm and then installing this unit into a seat 3 formed to this end inthe 0.76 mm thick plastic of the card 4.

This embodiment is very economical and can be distributed widely.

Another known type of memory card consists of a particular treatment ofone or more standard memory elements connected into a rigid printedcircuit to which is also connected a connector that is then insertedinto a plastic support of credit-card size. The connector has a greatmany address-line contacts, the number increasing with the memory of thecard.

This latter type of memory card is above all used in printers as supportfor supplemental-characters sets or in pocket computers to replace themagnetic disks which are usually mounted in portable computers.

FIG. 2 shows the construction of this type of card. The chips 5a formingthe memory are secured as is (chip-on-board technology) or in a casing5b and are connected to the traces of the printed circuit 6 usuallyformed of epoxied fiberglass. Data transmission takes place through aconnector normally fitted at, the end of the printed circuit and formedeither by contacts 7 formed by conductive deposits directly on theprinted circuit or by a collection of mechanical connections 8 mountedbeforehand in a plastic housing 9 which is mounted at the edge of theprinted circuit, the contacts being soldered to the traces of thecircuit.

The printed circuit is then sandwiched between two plastic housinghalves 10 to form the memory card.

This technology is expensive with respect to the other system describedabove and does not allow this type of memory card to be distributed morewidely than in the professional world.

The main reasons necessitating this embodiment are:

the need of putting together several chips of less capacity over a largesurface,

the large number of contacts used by large-capacity memories which takesup a significant amount of space along one edge of the card.

In fact the amount of memory provided in this type of memory card isnormally from 256 kilobytes to several megabytes. This memory sizerequires for random addressing at least 18 address lines which requires,in addition to eight information lines and four or five selection linesfor read/write, ground, and power, forming part of, at least 32electrical-connection lines (for 256 kilobytes).

With the increase of memory capacity per chip the surface area of therequired circuit will decrease to leave as the sole obstacle the highnumber of contacts.

OBJECT OF THE INVENTIONS

It is an object of the present invention to eliminate this last obstacleso as to make large-capacity memory cards suitable for dissemination toa large number of people thanks to their realization through theearliest technology.

SUMMARY OF THE INVENTION

To achieve the invention objects a particularity of the use ofinformation in this type of memory card is used.

In effect these memory cards are used as mass memory and their contentsis transferred when they are used into the active memory of the usersystem. For use in pocket computers the programmers have createdprograms derived from those which allow working with information on diskso that these cards are considered like this by the system of the usersystem.

Thus in every case the transfer of information to the active memory ofthe user system is done in a sequential eight-bit or word-by-wordmanner. The architecture proposed for the invention uses thisparticularity that allows one to avoid the multicontact address busnecessary for random access.

SPECIFIC DESCRIPTION

FIG. 3 shows the internal architecture of the invention.

The addressing system of the invention is formed by two up/down counters11 and 12 integrated into the memory element, the former of 8 to 16 bitsand the latter of 10 to 18 bits that are connected in parallel andinterconnected by a holding line R and that receive pulses from the usersystem, each through a single line. A pulse in the 8-16 bit countermodifies the address by one. A pulse in the 10-18 bit counter modifiesthe address by 255 to 4096. One or the other of the counters can beincremented or decremented separately according to the logic level of athird line. The decoding of the contents of the counters by the decoder13 allows addressing the byte sought which can be found rapidly. Ineffect the frequencies now used (12 Mhz) allow high transfer rates (12Mo/s) and a movement of the address of 1 megabyte in severalmilliseconds.

The addressing of the bytes held in the memory card is thus done throughthe following three lines:

    ______________________________________                                        Address counter 1       CA1                                                   Address counter 2       CA2                                                   Increment/decrement     INC/DEC.                                              ______________________________________                                    

The other contact lines on the card are:

    ______________________________________                                        Data                    D0-D7                                                 Electrical supply for the card                                                                        VCC                                                   Ground                  GND                                                   Read command            OE                                                    Writing programming     PGM                                                   Writing supply          VPP.                                                  ______________________________________                                    

The two last-mentioned lines are provided because the memory card isformed partially of a programmable memory and partly of an electricallyprogrammable and erasable memory. The programmable memory 14 stores datarelating to the type of internal configuration (size of up/downcounters, size of the memory . . . ) and the method of using the card.The electrically programmable and erasable memory 15 stores theaddresses of the last parts of the memory read or written during thelast use. The remaining memory 16 serves to store text, images, orprograms and can be of the one or the other type.

The connector of the memory card of the invention is limited to 16contacts even though it can hold memory to 268 megabytes.

A variant can reduce this number of lines to ten by transmitting theeight data bits serially on a single line thanks to a shift register.This method performs less well and requires a clock and asynchronization line.

The invention as described above can be easily put in practice withknown technology and can be use to disseminate information or consumerapplications such as electronic games or electronic books which are readby an apparatus provided with a liquid-crystal display.

The data in memory in the card can need to be protected and the writersof programming, games, or books distributed in this form can want tolimit the number of users of the same work. To achieve this theinvention can have two code registers each containing eight bytes thatcan only be written. One register 17 is definitively configured with anASCII password chosen by the buyer of the item when he purchases thecard or by the first user. The other register 18 is a nonpermanentrandom-access memory which is configured for each use of the card. Abit-by-bit comparison of the two code registers by a comparator 19 canby means of a simple system of AND or NAND gates give access to the areaof memory holding the data to be used thanks to a latch 20 operated by adecoder 21 which decides which memories to lock. Data comes or goesthrough a buffer 22 itself operated by a reading/programming circuit 23.

The architecture of the card having been explained, FIG. 4 shows apossible configuration of the contacts of the card. This configurationcorrespond to the two positions of contacts described in ISO standard7816-2 of October 1988 used at the same time.

Other variants of the connectors can be imagined without leaving thescope of the present invention and the application retains theexclusivity of all embodiments covered by the following claims.

I claim:
 1. An independent and portable electronic memory card for usein a reading and writing apparatus, said memory card comprising:acard-shaped support; a memory element on said support; an 8-to-16 bitfirst up/down counter on said support connected to said memory elementfor addressing said memory element by 8 to 16 bits; a 10-to-18 bitsecond up/down counter on said support connected to said first counterby a holding line and connected to said memory element for addressingsaid memory element by 10 to 18 additional bits; and a connector on saidsupport for connecting said memory element and said up/down counters tosaid apparatus, said connector comprising:a first contact fortransmitting pulses independently to said 8-to-16 bit first up/downcounter to increment or decrement an address of said memory element by 1at each application of a pulse to said 8-to-16 bit first up/downcounter, a second contact for transmitting pulses independently to said10-to-18 bit second up/down counter to increment/decrement said 10-to-18bit second up/down counter by 1 and increment or decrement said addressof said memory element by 2⁸ to 2¹⁶ at each application of a pulse tosaid 10-to-18 bit second up/down counter, a common exclusive thirdcontact connected to both of said counters for transmitting to saidcounters an electrical signal for determining by a logic level of saidelectrical signal the incrementing or decrementing of each of saidup/down counters, a set of eight data contacts (D0 to D7), an electricalsupply contact (VCC), a ground contact (GND), a read-order contact (OE),a program/writing-order contact (PGM), and a writing-supply contact(VPP).
 2. The independent and portable memory card according to claim 1wherein said connector comprises an array of 16 contacts including saidfirst, second, third and further contacts, arranged.
 3. The independentand portable memory card according to claim 1 wherein said memoryelement:includes a consultable programmable memory for recording aninternal configuration and method of using the card.
 4. The independentand portable memory card according to claim 1 wherein said memoryelement:includes an electrically reprogrammable and erasable memory forrecording an address of last data read or written as of a last use ofthe card.
 5. The independent and portable memory card according to claim1 wherein said memory element:includes an electrically programmablememory for recording text, images, and programming data.
 6. Theindependent and portable memory card according to claim 1 wherein saidmemory element:includes an electrically reprogrammable and erasablememory for recording text, images, or programming data.